Method of producing the cutting portion of tools



Oct. 31, 1944. J. R. JAMIESON METHOD OF PRQDUCING THE CUTTING PORTION OFTOOLS Filed Se i. 3, 1941 n o S e .L m RJ n m m m J m.

Patented Oct. 31, 1944 ME'rnon or PRODUCING THE CUTTING 1' PORTIONOF'TQOLS Jay R: Jam-ieson, Cleveland, Ohio Applicationseptember 3, 1941,Serial No. 409,342 I 10 Claims.

My invention relates .to .tools. and. more particularly to tools:for-cutting. and stripping. -in-- sulationfrom'wires and to an improvedmethod of producing such .tools.

In making electrical. connections with conduc- 'tive wires having.insulated-covers, it-is desirable.

to provide. a simple. tool for readily removingportions'. of theinsulationf'rom the wire. Heretofore, in providing tools for suchpurposes,.-it;has.-

beenthe practice tozprovide either a somewhat complicatedtool or adevice which is adapted to. be attached'to tables, benches; or the like.For

simple operations, such to.ols..or devices are not In Sim-.2

only cumbersome but are alsoexpensive. pletools whichhave beendevisedfor'suoh'purposes, thecutting edges of the tool is not only usuallyexposed but such tools are generally con.-.

structed in such. a manner that it is difiicult to strip theinsulationfrom the. wire after the cutting: operation.

It is an object of the presentinvention to pro-= vide an improved :toolfor cutting andstripping insulation from wires that. may be constructed.

by simple forming operations, is effective in service, and which iscomparatively small'in size so that it maybe readily carried inthepocket or kit of the electrician or operator, and to anim-- provedmethod of producing such tools.

I Another object of my invention is to providean improved tool having acutting portion anda handle; the cutting portion being integrally orfirmly united to the handle so that thetool may' beheld firmly incontact with the insulation during both the cutting and strippingoperations.

A further object of my invention is to provide an improved'tool that maybe readilysharpened Fig. 3 is aside elevational view with parts in.

section of a modification of my improved tool,

showing the cutting edges in thesame .plane as. one of the=faces of thedisk and the disk. at-

tached to a woodenhandle;

Fig.4 isafront view of'a ,disk having a central.

opening, the disk being embossed in preparation.

for subsequent operations; I

Fig.5 is. a cross sectional view onthe line 5-5 of Fig. 4;.

Fig. 6 is front view-of the completed disk;

Fig. 7 is: a cross-sectional view on the line 'l'1.

* of Fig- 6, showing the contour of the cutting edges, the dotted lines.indicating the portion. of the embossment which has been removed',"

Figs. 8 and 9 are detailviews showing modifications of thecuttingnotches or slots formed thedisk;

Fig. 10 is a perspective View of: a modified form of cutting andstripping tool. adapted to be uti-- lized .in; cutting and strippinginsulation from wires. having: a comparatively large-diameter;

Fig. .11 isa plan view of aportionof the blank from which the .toolshown in Fig. '10 is formed, the blankbeing shownembossed and the dottedlines; indicating. the planes upon which the. metal is bent in. formingthetool;

Fig. -12 is. a. crosssectional .view on the line |2l2 of Fig. 11;.

Fig. 13. is ailongitudinal sectional view of...a portion of the;tool-.shown in Fig-10, parts of the tool being shown embedded intheinsulation of the wire;.and

Fig, 14 is across sectional view on. the line l4-l4of Fig. 13.

Referring to. the modifications-.shownin Figs- 1 to '7, inclusive ofthe. drawing, my improved tool comprises, a diskl which is firmlysecured. to ahandle. 2 by any suitable, means, suchas a screw 3, or whenthe handle is formed of metal, the end portiorrof the metal may beextended through a centraljopeningin the diskandzbent' or. flangedoventhe. metal disk as shown at .311 in Figs. 1 and.2.

As illustrated the .disk .I has three cutting: slots or notches 4, 5 andIL-each of which: is: adapted to: receive .an insulated-wire of -adifferent. size;v althoughobviously the disk may be: provided withasmaller or. larger'number .of such slots or notches. Eachmof'theslots isprovided with cutting edges 7a and-8a whichare, adapted to cut theinsulation from the wireasit is forcedinto the slots.

According to'my inventionrthe cutting edges'.

7a and. 8a. .are formed 1115.8 simple. and economical manner. As.indicated-in Figs: .4;and' 5, 10f the. drawing, embossments. areformedin: the disk.

which is to be subsequently formed and I do not 4 desire to be limitedin this respect. For instance,

the embossments may be rectangular in shape. Preferably, however, theembossments extend from the outer periphery of the disk to a point asubstantial distance from the center and the side edges of theembossments converge toward each other and are rounded at their innerportion into various shapes as illustrated in the drawing. As shown inFig. 4, the outer edges I of the embossments are rounded in asubstantially spherical shape, in Fig. 8 the outer edges of theembossments terminate in a substantially circular portion as indicatedby the numeral ll, while in Fig. 9 one of the outer edges of theembossments extends substantially radially and the other edge is roundedoutwardly as indicated by the numeral l2.

After the embossments are formed, the metal forming the embossments islaterally ground to remove a sufiicient portion of the embossments toform slots or notches having sharp cutting edges whichextend toward theopening in the slot. The lateral grinding or the rounded portion of theembossments also serves to form a rounded inner portion with cuttingedges extending toward the slot. The embossmentsmay be of the same sizeor of different sizes. When the embossments are of the same or of astandard size, slots having various sizes may be provided by grindingthe embossments to various levels or if different size embossments areformed, slots of various sizes may be produced by grinding to the samelevel.

As illustrated in Fig. 5, the metal may be ground to a plane asindicated by the line XY to form cutting edges 1 and 8 in which theouter and inner portion of the metal of the cutting edge are at an acuteangle to each other.

To enable the tool to be readily sharpened when it becomes dull,however, theembossments are usually ground to a plane spaced from thefront face of the metal as indicated by the line AB or CD to formcutting edges la. and 8a as shown in Fig. l orcutting edges lb and 8b asshown in Fig. 5. Instead of grinding the metal to the plane designatedby the lines X-Y and AB, the upper portion may be cut or punched outupon a line havinga contour sub-' stantially vertical with edges l and 8or Ia and v 8a, thereby removing the maiior portion of the embossment,and the remaining metal maybe ground down to the desired level. Forinstance, the metal may be punched or cut out on a'contour such as shownby the openings of the slots in Fig. 6 and the edges of the metal maythen be ground laterally down to the shape shown in Fig. '7. It is notessential, however, that the embossments hall be formed prior: to thecutting or piercing operation as slots may be first punched from themetal and the sides of the metal adjacent each slot may be formed orextruded outwardly to provide metal surfaces extending beyond the normalplane of the metal,

such as shown in Fig. 14 which may then be ground to the desired level.

In the preferred form of my invention, however, a second embossment isformed within the firstembossment, as shown in Figs. 4 and 5, bothembossments being-formed in onestamping operation, and the metal formingthe second embossment is ground to a plane as indicated by the line CDto form cutting edges lb and 8b.

In the latter case the angle formed between the inner and outer edges ofthe metal is not atsuch is ground to a plane along the lines X--Y or ABand consequently the metal forming the cutting edges is not so apt to bebroken during the cutting operation. When the metal is formed in suchmanner, the second embossment may be completely removed without anypunching operation and the cutting edges are spaced outwardly from theface of the disk and are conse quently in a position to be readilysharpened when they become dull, or after they have been sharpenedseveral times, they may be ground down sufiiciently to form a cuttingedge for a wire of the next larger size.

After the embossment on the disks have been ground, the disk is in theform shown in Fig. 6 with the cutting edges converging radially inwardlyand terminating in a rounded portion with cutting edges, or the roundedportion of the slot may be more pronounced as indicated by the numeralI6 in Fig. 8, or it may be slightly offset as indicated by the numerall! in Fig. 9. It will be particularly noted that the outer faces of thecutting edges are substantially flat and that the cutting edges form theboundaries of the slot. The cutting edges are therefore not.

the handle is made'of metal, the end of the handle attached to the diskis preferably bent inwardly to form a shoulder l9 and is then ex-'tended through the aperture and-bent back or flanged over the disk. Theshoulder and flanged portion thus formed preferably extend approximatelyto the inner portion of notches l5 and form a firm support for the disk.

When the handle is formed of wood as shown in Fig. 3, the disk may beattached to the handle by any convenient means, such as a screw, 3,which extends through the aperture 18 and is embedded in the wood. If aplastic material is used, a threaded insert may be embodied in theplastic during the molding operation which protrudes beyond the end ofthe molded material to receive the disk and a. nut for securing the diskin place. In attaching the handle in the manner specified, it willv benoted that the central part of the disk fits snugly against the fiat endo'f the handle and that substantially the entire area of the diskextending radially inwardly from the notches bears against the end ofthe handle. The handle therefore provides a strong rigid support for thedisk.

In stripping insulation from wires, the insulated wire is insertedthrough the appropriate slot in accordance with the size of the wire andinto the rounded portion at the end of theslot. As the insulated wire isforced inwardly; the edges la and 8a cut the insulation. To insurecomplete cutting of the insulation, the wire is held in one hand and thehandle in the other, and after the wire has been inserted through theslot into the rounded portion, [the handle is turned to make a completecut and is then pulled to remove the insulationfrom the end of the wire.To insure proper cutting of th insulation and to provide a better gripon the insulation for stripping purposes, I have found it desir-' disk 6is atportion as-ind-icated am Kiri-Fig.6; or -ifdesire d thedin'nenportionof thaslotinay be substantially circular-as shown at- I 6; or maybecfiset' as-shown at-il 'in' Figp In the modifications shown-in FigWand- 9, -iti willbe understood that the rounded portions as well asthe: sides ar-e pro- Vi'dect with =cuttin'g edges;

A modifie'd fornr of my invention is: shown in Ffgs i lfl to :14 'ofthedrawing: and is-designed for cutting insulation -frm1. wires 1 ofcomparatively largeifdiametersf Aseillustrated, the handle is formedintegral with the cutting iportionv. of the to'olgthes toolbeing-preferablyformed. of an intea- 'gralspiec'e' of 2 metal;Aszindicated in Fig.1 102 of then-drawing;thea-metal fromiwhich the toolis formed-- is' bentz downwardlyat; both sides andcuttingJ-portion-With' diverging sidewalls and a horizontallyextending:puttingportionwith diverging- ;side: walls.

In cutting-insulation with 12116113001 shown in Figsto 14, inclusive,cutting-edge 22 is forced downwardly throug-hthe top of the insulationand cutting-edges '23 and 24 ,split the insulation alonghthe-sidesand-as the tool is pulled for- -wardly; the insulation is-removed as itis slit.

Intheformof tool-\shownin Figsbl to 7, inclu- I sive,- of the drawing,means. may also be provided to. out both the insulation andthe wire. Forthis pu rpose, one.of theembossments on the disk may be, formedwithbothlouter edges extending radiallyfin'ward and consequently whenthis embossment is' ground l-aterally-,vV-shaped cutting edges 253mformed. Iniforcing the insulated wire into aislo t of this type, itwillbe apparent that the edges 25tvill -out both the insulation and thewire.

It'willfbenotedthatcutting edges-25 'of this embossment are; spacedoutwardly from the plane otthemet'al'and consequently they may bereadily sharpenedwhen they become dull.

What I claim is:

1. The method of preparing the cutting por-- tion of an insulatingcutting tool which comprises shaping a portion of a flat sheet of metalto form an embossment protruding outwardly from the normal plane of themetal and having a concave inner surface and converging side wallsextendbossment :and' in a directitm :subs'tantiallyvpenpendicular:thereto: to: form: a substantially; v shaped slothaving'rrcutting edges:facing-search other aandiwitht; the narrow portion l of-l :the; ..V-shapedaslot spaced inwardly fronr the outer edge of: th'e .:metalwithout =disturbingthe metal in the norma'l'xplaneaot the-sheet:-

3. The method of preparingiadisk composed .ofr. fiatsheet metal to:.fo'rm' the; cutting portion 1 iofratooll which comprises: shaping:japortion of theadi-sktotform arr-embossment protruding outing inwardlya substantial distance from the shaped slot spaced inwardly from theouter edge of the metal without disturbing the metal in the normal planeof the sheet.

2. The method of forming the cutting portion of an insulating cuttingtool which comprises extruding from a flat sheet of metal a portionthereof in the form of an embossment having converging side wallsextending inwardly from the edge of the metal and then grinding themetal along substantially the entire length of the em- 76 wardly'fromthe normal-plane of the metal and having: a concave inner surface and.converging side walls extending inwardly toward the. center .from ithe: outer; periphery of the-disk" and then grinding away throughout:substantially the entire lengthsoft the embossment and substantiallyperpendicular-thereto 'asufiicient amount; of metal constituting thecentral portion oi-the embossment to z form a 1 substantially V-shapedslot having: cutting edges-facing-each other and of sufficient .sizetoreceive and cutthe insulated portion of -arwire as .it is. forcedinwardly through the-slot.- p

4; Themethod of preparingv a disk composed of flat sheet metal to. formthe cutting portion of. a. toolpwhich comprises. shaping portions .ofthe disktto formvaplurality of spaced. embossmerits oil-different sizesprotruding outwardly (from the'norma'l plane of the metal. and each ofwhich has side walls converging inwardly toward the centerwof the diskfrom. its outer periphery,.and. then grinding away along the entirelength of each embossment and in a direction substantiallyperpendicularthereto a sufficient amount o f .metal from thecentral, portion ,of eachembossment to form V-shaped slots of different sizes, ,each of which hascutting edges facing each other ofsufiicientsize to receive and out theinsulation fromv a wire.

5. The. method oipreparing a disk composed of flat sheet metal toform-thecuttingportion of a tool. which comprises shaping the. disk i toform an embossment: protruding outwardly from g the normal plane. of themetal having: a concave inner surface andlsid'e walls tapering frornithe.outer..periphery,of the disk towardthecenter and at least one of saidside walls being rounded outwardly adjacent its inner portion and mergedwith the other side toform an enlarged arcuateshaped portion spaced fromthe center of the disk and then grinding away along substantially theentire length of the embossment and in a direction substantiallyperpendicular thereto a suflicient amount of metal constituting thecentral portion of the embossment to form a substantially V-shaped slothaving cutting edges facing each other and of sufficient size to cutinsulation from an insulated wire forced inwardly through the slot andto form an arcuate-shaped opening having cutting edges to receive thewire after it has been forced inwardly through the slot.

6. The method of preparing a' disk composed of flat sheet metal to formthe cutting portions of a tool which comprises shaping the disk to forman embossment protruding outwardly from the normal plane of the metaland having a concave inner surface and side Walls tapering from theouter periphery of the disk toward the center of the disk and thengrinding away along substantially the entire length of the embossmentand ina direction substantially perpendicular thereto a sufiicientamount of metal The method of preparing constituting the centralportionof the embossimenttto 'form a substantiallyr V-shaped .slothaving cutting edgeszfacing each .other and of sufiicient size to cutinsulation from an insulated wire forced inwardly throughvthe' slot butsaid grinding being insufiicientto'reduce .any portion of saidembossment to the'normal .plane or the'metalinsaid sheet.

a disk composed of flat sheet metal to form the cutting portion of atool which comprises shaping the disk to form an embossment, protrudingoutwardly from the normal plane'of the metal having a concave innersurface and side wallstaper'ing from the outer periphery of, the disktoward the center maiorz r no t s 'eon 6 995 811 2 o m a u ta t a ly hadn l t haw ine ui ies edges facing each other andextending substantiallythe entirelength of-the' first embossment.

9. The method of, preparing a dislc'composed of fiat-sheet. metal toform the cutting portion of a tool which comprises shaping a portion .ofthe disk;to formva'first embossment, protruding outwardlyirom the normalplane of the metal at least one of which'is rounded outwardly -ad- Vjacent its inner portion and merged with the other side wall to form'an'enlarged 'arc'uateshaped portion spaced from the center of the disk, andthen laterally grinding away along substantially the entire length ofthe embossment and in a direction substantially perpendicular thereto a'suificient amount of metal constituting the central portion of theembossment to form a substantially V-shaped slot hav- ;ing cutting edges'facing each other and of sufficient size to cut insulation from aninsulated wire forcedly inwardly through the slot and to formariarcuate-shaped opening to receive the wire after ithas been forcedinwardly through the slot but the extent of said grinding beinginsuflicient to reduce any portion of said embossment to the normalplaneof the metal in said sheet. w 8. Themethod of formingthe cutting portionof a tool which comprises shapirig a portion of the fiat sheet of metalto form a first embossment protruding from the normal plane 'of themetal and having converging side walls extend ing inwardly a substantialdistance -from the *outer edge of the'metal and a second embossmeritprotruding from the first embossment having a concave inner surface and.converging side walls extending inwardly from the-outer edge of themetalto substantially the same distanceas the side walls of thefirstembossment and then laterally grinding away the metal constituting aV-shaped slot having'cutting edges facing each other and of suflicientsize to cut insulation from an insulated wire forced inwardly throughthe slot and an arcuate-shaped opening having cutting edges to receivethe wire after it has been forced inwardly through the slot.

g 10. The method of forming the cutting portion ofan insulatingcuttin'g'tool which comprises shaping a fiat sheet of metal to form anemjbossmen't protruding outwardly from the normal plane ofthe metal andhaving a concave inner surface and side walls tapering from the outeredgeof the metal which'merge'to form a rounded portion, grinding awayalong substantially the entire length of the embossment and in adirec-"tion substantially perpendicular thereto a sufficient "amount of metalconstituting the central portion ofv the embossmentto form a'substantially V shaped slot havingcutting edges: facing each other and acutting edge facing the slot,

and 'thenbending the metal beyond'the embossment and substantiallyintermediatefthe length of the embossment to form a [substantiallyyeshaped cutting portionand side'cutting portions diverging away fromeachother.

JAY R. JAMIEsonI

